The killing of Hassan Lakkis, a senior Hezbollah official, was done by Israel, the militant movement charged in a statement.
Lakkiswas killed overnight outside his home in the Hadath districtin Beirut as he was returning from work, the statement said.
Hezbollah described Lakkis as"one of the leaders of the Islamic resistance"against Israel and said the Jewish state had tried to kill him several times in the past.
The accusation comes a day after Hezbollah leader Hassan Nasrallah accused Saudi Arabian intelligence of being behind last months twin suicide bombings, which targeted Iranian embassy in the Lebanese capital.
Thebombingson November 19 killed 23 people. An Al-Qaeda-linked group claimed credit for the attack.